`TORUS´: a slotless, toroidal-stator, permanent-magnet generator

TORUS is a compact electrical machine particularly suitable for use as an engine-driven generator and which, when supplied via suitable switching circuits, can operate as a brushless DC motor to start the engine. The machine is of simple and cheap construction and gives high efficiency. The use of neodymium-iron-boron permanent magnets gives good utilisation and small overall size and weight. Several 2.5 kW prototype machines have been built and tested, and have demonstrated all aspects of performance and capability of the TORUS configuration in the generating mode